In recent years, downscaling of semiconductor integrated circuits has been increasingly accelerated. Along with the downscaling, it becomes difficult to detect defective portions (Hotspots) on an integrated circuit pattern formed on a semiconductor substrate. Conventionally, a Die-to-Die inspection of comparing actually transferred patterns is mainly conducted for detection of Hotspots. However, along with the downscaling of semiconductor integrated circuits, it is highly likely that a Die-to-Database inspection of comparing an actually transferred pattern with design data becomes a mainstream inspection. In the Die-to-Database inspection, the actually transferred pattern is compared with the design data and Hotspots of the transferred pattern are detected at predetermined defect detection sensitivity. Therefore, inspection data based on which the comparison is performed at the time of inspecting the transferred pattern is important. However, the design data is not necessarily appropriate as the inspection data as it is, due to process fluctuations such as a misalignment in an exposure process. Therefore, it has been desired to provide appropriate data as the inspection data used in the Die-to-Database inspection.